Top 10 2004 Chevrolet Avalanche Questions & Answers

I have the solution to every one out there with tailgate lock problems......I had the very same problem but wasnt interested in getting a power lock.......Here goes.....it costs you some wd40 or liquid wrench.....nothing else......open the tail gate.....you will see the screws that hold the handle in place.....take off the two outer screws only....then pop off the handle cover....yes it does come off without breaking.....you will see something shaped like a "C".....it should move back and forth.....with the tailgate closed you should be able to move that "C" back and forth...it swivels on a pivot you can see in the opening above the tailgate handle.......this is the lock mechanism.....mine was seized up.....anyways......with the tailgate still closed squirt some wd40 or liquid wrench in the area directly above the tailgate handle........that "C" thing will move again and your problem is over...email me if you figured it out........
I was delighted with the fix.....and it's so easy to do.....then put everything back in its place......tell everyone you know....

your mode actuator is stuck. try unhooking battery for a few minutes when you hook back up actuators will do a relearn.if this does not work will need to have replaced

Hello;
Are you getting the check engine light? If so the electronics may have gone out. You may not need a rebuild but you won't know till you pull the oil pan on the transmission and inspect the contents. You may also have lost the neutral safety switch. It is mounted on the drivers side of the transmission. Check those out first and let me know what codes you get.
For Ponchoboy; the clunking and hissing you hear are teminal root causes. Drop the oil pan and if it has a lot of filings and metal it is time for a rebuild.
Hope this helps; Rate me highly;
Rich
RPM Northwest

It's a good bet that the synchro for reverse is completely shot. The linkage is highly unlikely, as if it were mis-adjusted or damaged you would not likely be able to shift into park. A mis-adjustment to that side would cause you to actually be in reverse when it indicates park, so we can rule that option out. Also, the shift solenoid is not a likely culprit in this case since you're shifting upward through forward gears just fine. I hate to say it, but it's pretty likely that synchro. Another possibility, though not very likely, is a plugged region in the transmission valve body. Although I don't think this is probable, it would be the least expensive and easiest to check. To check this, you can drain the transmission fluid, remove the pan, and visually inspect the lower valve body. While you're at it, it might be a good time to chage the transmission fluid filter. If the lower valve body shows no clogging or damage in any of the ports, you will need to disassemble the valve body and inspect the upper region where the actually "brains" of the transmission are. If you're not comfortable with delicate mechanical work, I'd really recommend taking this job to a skilled mechanic. Unless you are working in a very clean area and have experience and patience for working with very small parts, you're likely to have an upset. The valve body consists of many "galleys". Some automatic transmission rely on ball bearings that act as check valves. Others do not. For the most part you can safely remove the valve body without losing parts, but if it appears damaged or clogged and dirty, cleaning it would, again, be best left to a mechanic skilled in transmission work. Not every mechanic is a good transmission mechanic. Even after nearly 30 years of experience I hesitate when it comes to transmission rebuilds because of the specialized tools and amount of time and patience they take. Let me know if this helps, and if you don't find the problem there, we can keep trying.

what i've seen with the k series chevrolet trucks is that the wheel speed sensors develop corrosion where the sensor mounts to the hub. you can start by taking the sensor out and cleaning off the mounting surface with a wire brush. the process is:

1. raise front of vehicle onto jackstands
2. remove front wheels
3. remove the brake caliper, bracket and rotor on both sides
4. remove wheel speed sensor via 1 torx bolt (be carefull as the corrosion will cause the sensor to "stick" in the hole)
5. clean the mating surfaces with a wire brush so the sensor bolt hole and mounting surface on the hub is shiney again.
6. if you can, pick up a can of rust preventing primer and spray a little on the surfaces to prevent further corrosion
7. let paint dry
8. apply a thin fil, of grease to the sensor and the sensor mounting spot on the hub
9. re-install sensor
10. revers steps 3-1 for re-installation.

*process is the same for both sides.

this was a common problem on the k series trucks.

while your in there it wouldn't be a bad idea to check the sensors wires to make sure they arent broken. let me know if the repair works for you

Oil Pressure Sensor Testing

1. Check the oil level and correct as necessary. Turn the ignition switch on, but do not start the engine.
   
2. Disconnect the sensor lead at the sensor. The gauge should read full scale.
   
3. Ground the connector. The gauge should read at the bottom of the scale.
   
4. If the gauge functions properly, replace the sensor.
   

4.8L, 5.3L & 6.0L Engines

1. If necessary, remove the engine sight shield.
   
2. Disconnect the oil pressure sensor electrical connector.
   
3. Using J 41712 or equivalent, remove the oil pressure sensor.
   

Using J 41712 or equivalent, remove the oil pressure sensor.

To install:

1. Apply sealant to the threads of the oil pressure sensor.
   
2. Using J 41712 or equivalent, install the oil pressure sensor.
   
   • Tighten the oil pressure sensor to 26 ft. lbs. (35 Nm).
     
3. Connect the oil pressure sensor electrical connector.
   
4. If necessary, install the engine sight shield.
   

Radio Amp has died. Replace the Radio. The Amp/Pre Amp is built into the radio if this is stock. Buy a new one and install it.

Is there a check engine light on? The first thing I would do is look at the vent solenoid. GM has had issues with these either sticking closed or the filter getting plugged.

Find the charcoal canister. It will be mounted near the fuel tank. There should be a large hose attached to it. On the other end of that is is the vent solenoid. Remove it and see if you can fill the tank.

If you can than see if you can blow through the vent solenoid. With it unplugged you should be able to blow through it easily. If you can't than it is broken and needs to be replaced.

I beleive GM has updated the part and routing for that year. You can check with the dealer to see if that is the case.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

The most likely cause is a failed blend door actuator; however I recommend a little troubleshooting. First, can you hear a clicking sound behind the dash when you turn the setting to hot? If yes, it is certainly the actuator stripping its gears. If not, check to make sure the heater hoses are both hot as they connect to the heater core at the firewall (in the engine compartment). If one or both of the hoses do not get hot, there is a blockage caused either by an air bubble or a stuck water control valve in the heater hose. If the hoses are both hot, the indication is again the blend door actuator.

Below are instructions for replacing the actuator. Look at the diagrams carefully--the big arrows point to the front of the truck and the actuator is on the side of the heater box above the outlet duct that runs to the driver's side of the floor. Also, the actuator is expensive, so I recommend you make sure it's bad and shop around a bit to get a good price. To check out the actuator, first see if you can turn the blend door by hand. If you can't turn it, maybe it's jammed. Also, reconnect the actuator after removing it and see what it does when you turn the heater to hot.

Removal & Installation

1. Remove the floor air outlet duct extension (1) from the floor duct (2).
   

   

Fig. Remove the floor air outlet duct extension (1) from the floor duct (2)

Disconnect the electrical connection at the blend door actuator (#10 in pic below).

Fig. Blend door actuator and related components

Remove the blend door actuator mounting screws from the HVAC module.

Remove the blend door actuator as an assembly with the actuator cam.

Fig. Remove the blend door actuator mounting screws from the HVAC module

To install:

1. Install the blend door actuator as an assembly with the actuator cam.
   1. Line up the heater/defroster valve lever with the blend door actuator cam slot.
   2. Line up the A/C valve lever with the blend door actuator cam
   
   
2. Install the blend door actuator mounting screw to the HVAC module.
   1. Tighten the blend door actuator mounting screw to 14 inch lbs. (1.6 Nm).
   
   
3. Connect the electrical connection at the blend door actuator (10).
4. Install the floor air outlet duct extension (1) to the floor air duct (2).

Picture of actuator:

Its a 25amp circuit breaker marked "doors" in the instrument panel fuse box.